The adjective diaphoros carries two related meanings: (1) different or various, and (2) excellent, surpassing, or superior. In Hebrews, it is used in the latter sense to describe Jesus's superior name (1:4) and the superior, better covenant (8:6), establishing the letter's central theological argument of Christ's supremacy over all that preceded Him.
Hebrews' repeated use of 'better' and 'superior' (including diaphoros) constructs a sustained theological argument: Jesus is not merely another figure in Israel's story but the one to whom all of Israel's story pointed. A more excellent name, a more excellent ministry, a better covenant — the entire sacrificial system, priesthood, and covenant of Moses were shadows pointing to the substance found in Christ.